      <p>For instantaneous fields, a monthly mean is the mean of the
fields sampled at
the specified averaging period. </p>
      <p>For accumulated fields, a monthly mean is the mean rate of
accumulation of the
fields. </p>
      <p>
      <table border="3">
        <tbody>
          <tr>
            <th> KSEC1 element</th>
            <th> Contents</th>
            <th> GRIB octet</th>
            <th style="vertical-align: top; text-align: center;">Recommended
GRIB_API keys</th>
            <th style="vertical-align: top; text-align: center;">Coded
GRIB_API keys</th>
            <th style="vertical-align: top; text-align: center;">Comments</th>
          </tr>
          <tr>
            <td> 37</td>
            <td>
            <pre>ECMWF local GRIB use definition identifier.<br>16 = ECMWF seasonal forecast monthly mean data</pre>
            </td>
            <td> 41</td>
            <th style="vertical-align: top; text-align: left;">localDefinitionNumber</th>
            <td style="vertical-align: top;">localDefinitionNumber</td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td>38</td>
            <td><a
 href="http://www.ecmwf.int/services/archive/d/table/grib_class/">Class</a></td>
            <td>42</td>
            <th style="vertical-align: top; text-align: left;">class</th>
            <td style="vertical-align: top;">marsClass</td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td>39</td>
            <td><a
 href="http://www.ecmwf.int/services/archive/d/table/grib_type/">Type</a></td>
            <td>43</td>
            <th style="vertical-align: top; text-align: left;">type</th>
            <td style="vertical-align: top;">marsType</td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td>40</td>
            <td><a
 href="http://www.ecmwf.int/services/archive/d/table/grib_stream/">Stream</a></td>
            <td>44-45</td>
            <th style="vertical-align: top; text-align: left;">stream</th>
            <td style="vertical-align: top;">marsStream</td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td>41</td>
            <td>
            <pre>Version number or experiment identifier.<br>(4 ASCII characters, right justified)</pre>
            </td>
            <td>46-49</td>
            <th style="vertical-align: top; text-align: left;">expver</th>
            <td style="vertical-align: top;">experimentVersionNumber</td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> 42</td>
            <td>
            <pre>Number<br>  Ensemble member number.<br>  Control forecast is number 0,<br>  perturbed forecasts 1-nn.<br> </pre>
            </td>
            <td> 50-51</td>
            <th style="vertical-align: top; text-align: left;">number<br>
            </th>
            <td style="vertical-align: top;">perturbationNumber<br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> 43</td>
            <td> Zero </td>
            <td> -</td>
            <th style="vertical-align: top; text-align: left;"><br>
            </th>
            <td style="vertical-align: top;"><br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> 44</td>
            <td>
            <pre>System number<br>  The "scientific version" number.<br>  0 = RD experiment<br>  1 - 65534 = operational version number<br>  65535 = missing </pre>
            </td>
            <td> 52-53</td>
            <th style="vertical-align: top; text-align: left;">system<br>
            </th>
            <td style="vertical-align: top;">systemNumber<br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> 45</td>
            <td>
            <pre>Method number<br>  Distinguishes scientifically different forecast ensembles<br>  (eg different calibration/bias correction)<br>  0 = control integration (ie without data assimilation)<br>  1 - 65534 = operational version number<br> </pre>
            </td>
            <td> 54-55</td>
            <th style="vertical-align: top; text-align: left;">method<br>
            </th>
            <td style="vertical-align: top;">methodNumber<br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> 46</td>
            <td> Verifying month (in format YYYYMM)</td>
            <td> 56-59</td>
            <th style="vertical-align: top; text-align: left;">verifyingMonth<br>
            </th>
            <td style="vertical-align: top;">verifyingMonth<br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> 47</td>
            <td> Averaging period (eg 6-hour, 24-hour)</td>
            <td> 60</td>
            <th style="vertical-align: top; text-align: left;">averagingPeriod<br>
            </th>
            <td style="vertical-align: top;">averagingPeriod<br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td>48</td>
            <td>Forecast month</td>
            <td>61-62</td>
            <th style="vertical-align: top; text-align: left;">forecastMonth<br>
            </th>
            <td style="vertical-align: top;">forecastMonth<br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
          <tr>
            <td> -</td>
            <td> Spare (set to zero)</td>
            <td> 63-80</td>
            <th style="vertical-align: top; text-align: left;"><br>
            </th>
            <td style="vertical-align: top;"><br>
            </td>
            <td style="vertical-align: top;"><br>
            </td>
          </tr>
        </tbody>
      </table>
